Dispersion mill



Jmy 2, i940, M. W. DITTO DISPERSION MILL Filed June 27, 1939 4 Sheets-Sheet l 2W ZZ f My A 1940. M. W. om@ was@ DISPERSION MILL Filed June 27, 1939 4 Sheets-Sheet 2 July 2, 1940 M. w. DIT-ro 2,206,633

DISPERSION MILL Filed June 2'?, `19:59 `4 sheets-sheet s j 4% fi 47 July 2, 1940 M. w. DrrTo 2,206,633

DISPERSION MILL Filed June 27, 1939 4 Sheets-Sheet 4 PESSUEE meme July 2, 1940 PATENT yoFFlcE DlsrEasioN mm.

Marvin W. Ditto, New York, N. Y., assignor to Emulsions Process Corporation, New York,y N. Y., a corporation of Delaware Applicants June zr, 1939, serm- No. esisti4 24 Claims.

, I'his invention relates to improvements in dispersion or emulsiflcation mills.

'I'he primary object of the invention is to provide an improved type of mill designed to finely disperse two or more liquids of different characteristics or incorporate suspended matter such as talc, color pigment or any other finely divided material in one or more liquids psing through the mill.

` Another object is to supply a dispersion mill so designed as to render the internal elements selfcleaning due to the fact that such parts are constantly washed by liquid passing through the mill.

,15 A further object is to supply a dispersion mill description proceeds, the invention consists in the novel features hereinafter described in detail in connection with the accompanying drawings and more particularly pointed out in the appended claims.

In the drawings: Fig. 1 is a vertical sectional View partly in elevation of the inlet end portion of one embodiment of my improved mill. I Fig. 1A is a similar View of the discharge end portion. I

Fig. 2 is an end elevation partly in transverse vertical section.

Fig. 3 is a fragmentary transverse vertical section view of a modification.

Fig. 4 is an elevation of any one of the impulse orrepulse aims forming part of the mod- Fig. 5 is a longitudinal sectional view of the repulse arm taken on the line 5--5 of Fig. 4.

Fig. 6 is a transverse section View of such arm taken on the line -I of Fig. 4. Fig. 'I is a sectionalview of another type `of repulse or impulse arm.

Fig. 8 is an end elevation of the arm shown in Fig. 7.

Referring first to Figs. l, 1A and 2, 9 designates a hollow cylinder having a `jacket i0 to provide an annular passageway I I through which a heating or cooling medium may be passed for ccntrolling the temperature within the mill. Such medium may enter the passageway through an f5 inlet I2 and be discharged through an outlet I3.

I as will be apparent from an "inspection of the Plates I4 and l5 close the ends of the cylinder and are rigidlysecured thereto by any suitable means, such as stud bolts IB.

Such plates provide bearings' I1 and I8 of any suitable type to form journals for the ends of a driven shaft I9, extending centrally through the cylinder and rotated by any suitable prime mover (not shown).

Discs or supporting members 20 are keyed to the shaft and are preferably arranged in pairs, 10 the discs of each pair being secured together by any suitable means such as rivets 2 I. These discs function as mounting and carrying means for impulse arms '22 which, as best shown in Fig. 2, are arranged in radial rows -and project from opposite sides of the discs. Each arm is provided at its inner end with a head 23 that is counter-sunk in one of the discs, and as the heads of aligned arms abut against one another, the arms are held rigidly on the discs by means of the rivets 2 I.

Between the discsZll, the cylinder is provided with stationary annular flanges or supporting members 2li; these flanges also being arranged' in pairs, and the flanges of each pair being rigidly secured together by any suitable means such as screws 25. The flanges (like the discs 20) function to support repulse arms 26,' arranged in aligned pairs and in radial rows; the repulse arms 2t being staggered relatively to and overlapping the impulse arms 22. Each repulse arm 30 is provided with a head 2i counter-sunk in one of the flanges 2t, and as the heads of each pair of repulse arms abut one another, they are rigidly held in position due to the screws i5.

Each of the end plates It, I5, is provided with a lining plate tt that is secured to an end plate by any suitable means, such a's screws 29, and such lining plates are employed in the mounting of radial rows of repulse arms 30 in a manner similar to the mounting of the repulse arms 2t,

ows outwardly from the shaft I9 and around the first pair of discs 2li and then inwardly toward the shaft between said pair of discs and the flanges 24. Upon reaching an annular pas- M sageway 34 at the center of the flanges. it again passes outwardly between the flanges 24 and the second pair of discs then around the periphery of said pair of discs and inwardly until it reaches ports 35 in the end plate l5, which ports lead to an annular passageway 36 having a discharge outlet 3l.

Arrows on Figs, l and 1A indicate the flow of the stream.

As the stream passes through the mill', it is acted upon by the impulse and repulse arms and, as shown in Fig. 2, each of these arms has a concave face 38 and a convex face 39; the concave faces of the impulse arms facing in the opposite directions from. the concave faces of therepulse arms, and the convex faces of the impulse arms facing in the opposite direction from similar faces of the repulse arms.

Each arm has a substantially conical port dit extending therethrough, the port fiaring toward the concave face of the arm so that the liquid under treatment is forced to travel through such ports .and eect cleaning of the arms.

As before stated, the repulse arms are stationary and the impulse arms rotate counterclockwise so that the leading edges of the im pulse arms approach the leading edges of the `repuise arms at a rate oi speed equivalent to the rate of rotation of the rotor. Obviously the Vvelocity or peripheral speed of the impulse arms nearest the shaft i9 is slower than the rate of speed ofl the outer impulse arms, because of the diuerences in the distances of the various arms from the axis of the shaft.

vThe purpose of these armsis to obtain three important actions pertaining to the dispersion of liquids or materials within liquids; 11) turbulence, (2) impact, and (3) shear.

I have found in4 practice that with nely divided materials, such as pigments to be used in paints or lithographic inks to be incorporated in oils, there is a tendency due to impact and viscosity and tackiness ofthe oils, to build up materials undergoing treatment upon the surfaces and form in stream line contours which would be the equivalent to rotating a solid member ofmetal instead of a concave face approaching a concave face.v Therefore, one purpose of the special shape of each arm is to bleed sumcient liquid through the tapered hole i0 to make it self-cleaning, due to the fact that the inner face of the cups are constantly washed, by liquid passing through the discharge port 40.

It is a well-known fact that when moving a stream line body through an incompressible liquid, such as oil or water, there is (depending upon the shape of the body) va tendency to create laminar flow which' produces a minimum amount of turbulence,l or if the shape of the body is changed to disturb laminar iiow, there will be created' a ,zone of high turbulence in the wake of the moving member. In the type of construction illustrated, the intent is to create high turbulence and then interrupt such turbulence by the amount of liquid bleeding through the hole k40 into the zone of turbulence created by the motion of the arm through the liquid.'

It mustbe kept in mind to fully understand the principles incorporated in the mill, that while liquid is being forced in by a pump with sufficient pressure, to discharge against an outlet back proach one another, besides creating turbulence in the liquid, the liquid is tossed from the impulse arms to the repulsa arms. This not only imparts a high degree of impact to the materials undergoing treatment but the material in passing the leading edges of the arms is sheared and such shearing is very intense because of the relative velocity.

Normally my mill will be rotated at about 3600 R. P. M. and the materials passing through will be at pressures ranging from 100 to 3000 pounds per square inch depending on the materials undergoing treatment and the result to be accomplished. Therefore, I have by my novel construction devised a means whereby the rotor and the stator are self-scouring or self-cleaning, and the construction is such as to permit the development of the maximum physical reactions within the cell of yeast.

Instead oi making the impulse or repulse arms as shown in Figs. 1, 1A and 2, I may employ the construction shown in Figs. 3 to 6 inclusive.

In this case, each arm will have an 'elongated concave channel di in its forward face and a similar channel 42 in its rear face, but the mouth of the channel 4i will be wider than the mouth of the channel 42. Here also each arm Will be provided with a substantially conical port 43 extending from one face to the other end with its larger end extending toward the channel 4I. As the channels in this construction are wider than the neck 44 of the arm and therefore the arm cannot be inserted through either a disc or ange from the rear thereof, I provide each neck with a nut 45 to facilitate attachment to the disc or flange which carries the same.

Obviously in this construction each arm has a. concave surface at its leading side as Well as its trailing side and the purpose of this structure is to increase the area. exposed to the liquid in the forward motion but exposing it to a relatively wide concave surface, and in therear of the arm is a pocket, which if moved through the liquid at high enough Velocity (in the absence of the port 43) would create a partial vacuum, or if such an arm could be moved through the liquid at high enough velocity, a high vacuum would be created within the area of the rear cup 42.

In the treatment of yeast and/or its dispersion in the wort in the manufacture of beer, it is desirablel to open up or crack the wall of the yeast cell to release the enzymes fermented. When this reaction is accomplished in a machine of the type illustrated in Figs. 3 to 6 inclusive,

it will be seen that due to high positive pressure on the leading face 4| of the arm, there will be almarked differential in pressure between the front and rear of the arm, and as thesev two surfaces are inter-communicating due to the presence of the port 43, the yeast cell jetting through the port will give a very high positive pressure to the zone ofrelatively low pressure and have a tendency, due to the fact that the cell wall is relatively fragile, to open up and discharge the ferment contained therein.

In Figs. 7 and 8, I have illustrated another type of impulse or repulse arm suitable for my purposes. It comprises a nozzle 46 having a substantially conical port 41 extending therethrough and flaring toward the front end 48 of the nozzle. A spider 49 extends diametrlcally across the front end of the nozzle and has a threaded connection with a stem 50 which extends therethrough and is provided rearwardly of the outlet or smaller end 5l of the nozzle with a conical head 52, the

apex of which faces the outlet end-of the nozzle.

threaded connection with the nozzle. The nozzle in this instance has an interior contour which -is the equivalent of the contour of a perfect nozzle giving maximum nozzle velocity when liquid isy passing through end.

When such nozzles are attached to the rotor it from its front end to its rear plate and rotated through the liquid at 3600 R. P. M., the nozzle jetting velocity is extremely high and the impingement of the stream passing through the nozzle is deiiected by the conical tail piece 52, and as a result of displacement and high velocity, a zone of partial vacuum is obtained behind the tail pieces. As in the former case (Figs. 1, 1A and 2), the velocity of the nozzles is many times higher than the velocity of the liquids, therefore in passing through the repulse arms there is a shearing action resulting in turbulence and impact at the points where the impulse nozzles pass the repulse nozzles. Here again, due to the fact that the velocity of the liquid passing through the nozzle is extremely high, the nozzles are self-cleaning and will not permit the building up of materials which would tend to close over the nozzle openings. A Y

The construction of my impulse arms reduces the drag on the impulse members due to the turl bulence created in the wake of these members.

Material that is permitted to escape through the ports in such members to satisfy the drag created in the wake, reduces the amount of power required to rotate the rotor.

In each form of the invention it will be noted that the impulse and repulse arms are arranged in overlapping relation and `have confronting concave surfaces. Furthermore, each armhas opposite narrow side edge portions, so that such edge portion of the impulse arms, during rotation of the rotor, travel in circular paths adjacent to con` centric circular lines defining said side edge portions of the repulse arms, whereby said edge portions act on the materials passing between the adjacent edge portions of the'impulse and repulse arms.

From a study of the prior art, I believe I have invented a new type of mill for the purposes intended and that I am utilizing a new principle of dispersion heretofore unknown. The design of my machine renders itself to higher speeds than those indicated because by increasing the diameter of the cylinder t and the diameter of the rotor and stator, higher peripheral velocities will be attained at the periphery of the rotor and therefore higher differentials of relative speed between moving members and the liquid can be arbitrarily controlled. As my new design makes available a construction for extremely high speeds, obviously one can obtain a high degree of shear, impact be made in the details disclosed without departing from the spirit of the invention as expressed in the claims. What I claim and desire to secure by Letter Patent is:

1. A dispersion mill of the character described, comprising a casing, a rotor arranged in the casing, adapted to rotate about an axis, and having a supporting member, impulse arms projecting from one side of said member and having concave leading faces extending lengthwise thereof, a stator arranged in the casing and provided with a stationary supporting member, repulse arms secured to the supporting member oithe stator, projecting in a direction opposite to that of the impulse arms and arranged in staggered relation relative to said impulse arms, the repulse arms having concave surfaces extending lengthwise thereof and facing in the opposite direction from that of the concave faces of the impulse arms, means for admitting materials to be treated into said casing, and means for discharging treated materials from the casing, the impulse and repulse arms being arranged in overlapping relation and having confronting narrow edge portions, the edge portions of the `impulse arms being arranged in close proximity to the edge portions of the repulse arms to causeA shearing of materials passing between aid arms.

2. In a dispersion mill of the character de-A scribed, a rotor having a rotatable supporting i member, spaced impulse arms carried by said supporting member and projecting from one side of the supporting member, the impulse arms having concave leading faces extending lengthwise thereof, a stator comprising a stationary supporting member, stationary repulse arms supported by the supporting member of the stator and projecting from the last-mentioned member in a direction opposite to that of said impulse arms, the repulse arms having concave surfaces extending lengthwise thereof and facing in the opposite direction from that of the concave faces of the impulse arms, the repulse arms being arranged in staggered relation relative to the impulse arms and overlapping the latter, said impulse and repulse arms having confrontingmar-` lmember, spaced impulse arms carried by said supporting member and projecting from one side of the supporting member, a stator comprising a stationary supporting member, stationary repulse arms supported by the supporting member of the stator and projecting from the last-mentioned member in a direction opposite to that of said impulse arms, the repulse arms being arranged in staggered relationrelative to the impulse arms and overlapping the latter, and means constraining a stream passing through the mill to travel between seid supporting :new i whereby the stresm will be actedupon by seid impulse and repulse arms, erich erm having n concave fece, the

concave feces of said impulse end repulse arms having confronting narrow edge portions, the edge portions of the impulse arms being arranged in close prommity to the edge portions oi the repulse arms to ceuse shearing of materiels passing between said orme.

e. 'ln e dispersion mill oi the cheraeter described, e rotor having e rotatable supporting member, speced. impulse errno carried by said supporting member end projecting from one .side oi the supporting member, o stgtor comprising s stationary supporting member, stationery repulse erms supported by the supporting member oi the stator and projecting from the lesnmentioned member in a direction opposite to that of seid impulse erms, the repulse orme being arranged in steggered relation relative to. and in close proximity to the impulse arms end overlapping the letter, end means constraining e stroom passing through the mill to trnvel between seid supporting members whereby the stream will be acted upon by seid impulse and repulse arms, each impulse arm hoving an elongeted concave leading fece extending lengthwise thereof, end euch repulse arm having an oppositeiy facing elongated concave tace extending 'lengthwise thereof. f

5.121 a dispersion mill of the character de scribed, e, rotor having a rotatable supporting member, spaced impulse arms carried by said supporting member-and projecting from one side of the supporting member, a stntor comprising a stationary supporting member, stationary repulse erms supported by the supporting member of the stator end projecting from the last-mem tioned member in e direction opposite to that of said impulse arms, the repulse arms being arranged in staggered relation relative to the ini-V pulse arms und overlapping the letter, and means constraining a stream passing through the mili to travel between said supporting members whereby the stream will be acted upon by said impulse end repulse arms,each arm having a concave race end-e tapered port extending through the erm.

6. In s. dispersion mill of the character described, e, rotor having a rotatable supporting member, spaced impulse :arms carried by said supporting member and projecting from one side of the supporting member, a stator comprising e stationary supporting member, stationary re-l pulse arms supported by the supporting member oi the stator and projecting from. the last-merrtioned member in a direction opposite to that of said impulse arms, thev repulse arms being arranged in staggered relation relative to the im.- pulse arms and overlapping the latter, and means constraining a stream passing through the mill to travel between said supporting members whereby the stream will be acted upon by said impulse and repulse arms, the impulse arms having sub'- stantially conical apertures extending therethrough with the apex of the cone extending toward the trailing face of the arm.

'1. In a dispersion mill oi the character described, a rotor having 'o rotatable supporting member, spaced impulse arms carried by said `supporting member and projecting from one side of the. supporting member; a stator comprising a.

stationary supporting member, stationary repulse arms supported by the supporting member of the stator and projecting from the last-mentioned member in a direction oppositeto that of www@ mid impulse orme, the repulse orme being arrenged in steggered relation relative tothe im pulse orme and overlapping the latter, end means constraining e sti-eem passing through the mill to travel between seid supporting members whereby the stream will be noted upon by seid impulse end repulse srms, the srms 4being sub stentielly ifi-shaped in crosssection.

sin e dispersion mill o the character de scribed, s, rotor having a rotatable supporting member, spaced impulse arms carried by said of the supporting member, o stator comprising e, stetioncry supporting member, stetionery repulse orme supported by the supporting member of the stator and projecting from the lastmrnentioned member in e, direction opposite to that of seid impulse arms, the repulse arms being nrrenged in staggered relation relative to the im pulse arms and overlapping the latter, and means constraining e, stream passing through the mill to travel between said supporting members whereby the stream will be acted upon by seid impulse end repulse erms, certain or" the impulsel arms having concave leading faces and conver; trailing faces.

9. ln a dispersion mill of the character described. s. rotor hei/ing a rotatable supporting member, spaced impulse ernis carried by said supporting member and projecting from one side oi the supporting member, a stator comprising n stationary supporting member, stationary repulse erms supported by the supporting member of the stator andv projecting from the last-mentioned member in s, direction oppositeto that oi seid impulse grins, the repulse arms being arranged in staggered relation relative to the impulse arms and overlepping the latter, means constraining a stream passing through the mill to travel between said supporting members whereby the stream will be noted upon by said impulse and repulse arms, said impulse and repulse arms hav Jing confronting grooved races and narrow edge portions, the edge portions of the impulse arms being arranged in close proximity to the edge portions of the repulse erms to cause shearing of material passing between said arms and each oi seid arms having a substantially conical port eretending therethrough with its large end adjecent to thegrcoved face of the erm.

lo. in a dispersion mill of the character described, e, rotor having a. rotatable supporting inernber, spaced impulse erms carried by said supporting member and projecting from one side of the supporting member, n stator comprising a stationery supporting member, stationery repulse arms supported by the supporting member oi the stator and projecting from the last-mentioned member in a. direction opposite to that of said impulse arms, the repulse arms being arranged in staggered relation relative to the impulse arms and overlapping the latter, and means constraining a' stream passing through the mill to travel between said supporting members whereby the stream will be acted upon by said impulse and repulse arms, the arms being of non-circular shape' in cross section and provided with taperedv ports extending therethrough.

11. In a, dispersion mill of the character described, a rotor having a rotatable supporting member, spaced impulse arms carried by said supporting member and projecting from one side of the supporting member, a. statorv comprising a stationary `supporting member, stationary repulse arms supported by the supporting member of the `supporting .member and projecting from one side ldt stator and projecting from the last-mentioned member in a direction opposite to that o! said impulse arms, the repulse arms being arranged in staggered relation relative to the impulse arms and overlapping the latter, and means constraining a stream passing through the mill to travel between said supporting members whereby the stream will'be acted upon by said impulse and repulse arms, certain of said arms having front and rear elongated concave channels, and tapered ports extending through these arms from one channel to the other.

12. In a dispersion mill of the character described, a rotor having a rotatable supporting member, spaced impulse arms carried by said supporting member and projectingl from one side of the supporting member, a stator comprising a stationary supporting member, stationary repulse arms supported by the supporting member of the stator and projecting 'from the last-mentioned member in a direction opposite to that of said impulse arms, the repulse arms being -arranged in staggered relation relative to the impulse arms and overlapping the latter, and means constraining a stream passing through the mill to travel between said supporting members whereby the stream will be acted upon by said impulse and repulse arms, at least oneof said arms comprising a nozzle having a substantially conical passageway extending therethrough and provided at the small`end of said passageway with a conical tail piece having its apex facing the small' end of the nozzle. l

13. In a dispersion mill of the character described, a rotor having a rotatable supporting member arranged in a plane substantially perpendicular to the axis of rotation of the rotor,`

spaced impulse arms carried by said supporting member and projecting from one side thereof, a stator having a stationary supporting member arranged substantially parallel to the supporting member of the rotor and spaced from the latter, stationary repulse arms supported by the supporting member of the stator, projecting toward the supporting member of the rotor and overlapping said impulse arms, said repulse arms being arranged in close proximity. to the impulse arms but being staggered relatively to said impulse arms, said impulse and repulse arms having confronting narrow edge portions, the edge portions of the impulse arms being arranged in close proximity to the edge portions of the repulse arms to cause shearing of materials passing between said arms and means constraining a stream passing through the mill to pass between said supporting members whereby it will be acted upon by said impulse and repulse arms, some of said arms having tapered ports extending therethrough.

la. In a dispersion mill of the character described, al rotor having a rotatable supporting member arranged in a plane substantially perpendicular `to the axis of rotation of the rotor, spaced impulse arms' carried by said supporting member and projecting from one side thereof, a stator having` a stationary supporting member arranged substantially parallel to the supporting member of the rotor and spaced from the latter, stationary repulse arms supported by the supporting member of the stator, projecting toward the supporting member of the rotor and overlapping said impulse arms, said repulse arms being arranged in close proximity to the impulse arms but being staggered relatively to said impulse arms, and means constraining a stream passing through the mill to pass between said supporting members whereby it will be acted upon by said impulse and repulse arms, some of said arms having tapered ports extending therethrough and provided at the outer ends of the ports with sunstantially conical tail pieces.,

l5. A dispersion mill ,comprising a casing having an inlet at one end and anoutlet at the opposite end, a stator arranged-"inthe casing and provided with oppositely extending spaced repulse arms, a rotor arranged in the casing and provided with impulse arms which extend toward one another, the impulse arms overlapping the repulse arms, being `arranged in close proximity thereto and positioned in staggered relation relatively to the repulse arms, said impulse and repulse arms having concave faces terminating in inner` and outer confronting narrow edge portions, the edge portions of the impulse arms being arranged in close proximity to the edge portions of the repulse arms to cause shearing of materials passing-between said arms, each. impulse arm having a tapered port extending there through with its larger end arranged at the leading face of the arm. c

16. A dispersion mill of the character described, comprising a plurality of disc-like members positioned adjacent to one another, means for rotating one of said members relatively to the other, impulse and repulse arms projecting from said members and arranged inl staggered and overlapping arrangement relatively to one another, the arms of said members having confronting, elongated, concave surfaces and narrowedge portions, theedge portions of the arms of one member being arranged in close proximity to the ledge portions of the varms of the other member, each arm having a substantially conical aperture extending therethrough from its concave face toward its opposite face, and means constraining a stream passing through the mill to .travel between said members whereby said stream `will be subjected Iby said armsto violent turbulence, impact and shear.

17. A dispersionV mill of the character described, comprising a casing, a rotor arranged in the casing, adapted to rotate about an axis and having a supporting member, impulse arms projecting from one side of said member and rotatable therewith, a second member arranged in the casing, repulse arms secured to the second member, projecting in a direction opposite to that of the impulse arms and arranged in staggered and overlapping relation relatively to said impulse arms, means for admitting materials to be treated into said casing, and means for discharging treated materials from the casing, each of said arms having opposite elongated grooves, the grooves at one side of the impulse arms facing the grooves at the opposite sides of the repulse arms.

18. A dispersion mill of the character described, comprising a casing, a rotor arranged in the casing, adapted to rotate about an axis and having a supporting member, impulse arms projecting from one side of said member and rotatable therewith, a second member, repulse arms supported by the second member, projecting in a direction opposite to that of the impulse arms and arranged in staggered and overlapping relationrelatively to said impulse arms, means for admitting materials to be treated into said casing, and means for discharging treated materials from the casing, each of said arms having opposite elondit titl

dit

gated grooves, the grooves at one side of the imtu iid puise arms fac the grooves at the opposite sides oi' the repulse arms, each arm having a hole :i therethrough and plac its grooved surfaces in communication with one another.

i9, A dispersion mill of the character desribed, comprising a casing, a rotor arranged inthe casing, adapted to rotate about an axis and having a supporting member, impulse arms projecting from one side of said member, a second member arranged in the casing, repulse arms secured to the second member, projecting in a direction opposite to that oi the impulse arms and arranged in staggered relation relative to said impulse means for admitting materials to be treated into said casing, and .means for discharging treated materials from the casing, the impulse and repulsa arms being arranged in overlapping reiation and having confronting concave `sur-1 faces terminating in inner and outer narrow edge portions, the edge portions oi the impulse arms vming arranged in close proximity to the edge por.

tions oi' the-repulse arms to cause shearing voi materials passing between said arms, each arm having an aperture extending therethrough fronr its concave surface to its opposite surface.

2o. in. a dispersion mill oi the character described, a casing having an inlet and an outlet, a rotor in the casing having a rotatable supporting member arranged in a plane substantially perpendicular to the axis of rotation of the rotor, spaced circular serieslof spaced impulse arms carried by said supporting member and projecting from one side thereof, a stator having a stationary supporting member arranged substantially parallel to the supporting member of the rotor and spaced from the latter, and spaced circular series of spaced repulse arms supported by the supporting member of the stator, projecting toward the supporting member of the rotor into the spaces between the series'of impulse arms, said repulse arms being arranged in close proximity to the impulse arms, the impulse and repulse arms being rarranged in the casing between said inlet andfoutlet and having confronting concave surfaces, each arm also having opposite narrow side edge portions, said edge portions of the impulse arms during rotation of the rotor traveling in circular paths adjacent to concentric circular lines defining said edge portions of the repulse arms to cause materials passing between said edge portions ,of the impulse arms and repulse arms to be acted upon by said edge portions.

2l. In a dispersion mill comprising a casing having an inlet and an outlet, a stator arranged in the casing and provided with spaced circular series of opposite extending spaced repulse arms, a rotor arranged in the casing and provided with circular series of impulse arms which extend to`=I ward one another and into the spaces between the series of repulse arms, the impulse and repulse arms being arranged in the casing between the inletand outlet and having confronting concave surfaces, each arm also having offset narrow edge portions, said edge portions oi the impulse arms, during rotation of the rotor, traveling in circular paths in close proximity to concentric circular lines 'deiining said edge portions of the repulse arms .to cause materials passing between the escasas pulse and repulsa arms to be acted upon by seid edge portions.

22. A dispersion mili of the character described, comprising a casing, a stator arranged in said casing and comprising spaced circular series oi stationary repulsa arms arranged substantially parallel to one another, a rotor arranged in the casing and having circular series oi spaced im pulse arms arranged substantially parallel to the axis oi rotation and extending into the spaces be-= tween the series of repulse arms, the impulse and repulse arms having confronting concave sur faces, each arm also having opposite narrow side edge portions, said edge portions of the impulse arms during rotation of the rotor traveling in circular paths in close proximity to concentric cir= cular lines deiining said edge portions oi' the repulse arms to'cause materials passing between said arms to be acted upon by said edge portions,

. means for admitting a stream to be treated to one edge portion of said casing, and means for dis charging such stream from the opposite end-pontion of said casing,

\ 23. A dispersion mill of the character described, comprising a casing having an inlet and an outlet, a rotor member arranged in the casing and adapted to rotate about an axis, a circular series oi spaced impulse arms carried by said member and projecting from one side thereof, supporting means arranged adjacent to said member, circular series of spaced repulse arms secured to said means and projecting in a direction opposite to that of the impulse arms, said impulse arms pro-'- jecting into the space between the series of re p ulse arms, the impulse and repulsa arms .being arranged in the casing between the inlet and outr let and having confronting concave surfaces and narrow side edge portions, said edge portions oi the impulse arms, during rotation of the rotor, traveling in circular paths in close proximity to concentric circular lines dening said edge por-y tions of the repulse arms to cause materials pass-,- ing between the impulse and repulse arms to be acted upon by said edge portions.

2i. A dispersion mill of the character described, comprising a casing', a rotor arranged in the casing adapted to rotate about an axis and having a supporting member, spaced circular series oi spaced impulse arms carried by said member and projecting from one side thereof, a second sup-porting member arranged adjacent to but spaced from the iirst supporting member, a circular series of spaced repulse arms secured to the second supporting member and projecting in a direction opposite to that oi the impulse arms and into the space between the series of impulse arms, said impulse and repulse arms being arranged in close proximity to one another and hav= ing confronting elongated concave surfaces, each arm also having opposite substantially parallel narrow side edge portions, said edge portions oi the impulse arms during rotation of the rotor traveling in circular paths closely adjacent to concentric lines deiining edge portions of the repulse tween the impulse and repulse arms.

MARVIN W. DITTO. 

